Design of the Roura Native American flute

This page describes the design of the Roura Native American flute …
a Native American flute constructed out of PVC.

The name Roura is from the Czech word for pipe or tube.
When I first met Jirí Stivín
[yi-zhee sti-vin]
in Prague,
in addition to playing silver flute, recorder, and alto sax,
he played a little white flute that he called a roura.
I searched on the Internet and in the library for references to the musical
instrument called “roura”, but came up with nothing.
Then next time I saw him, I asked about the instrument.

“Ahhh, that is my own flute …
I made it with a knife …
every flute player should make his own flute!
It is from plumbing tube …
in Czech the word ‘roura’ means pipe or tube“

So I call this a Roura Native American flute.
It sounds reasonably good…

… and has a few unusual characteristics that made
people ask me to publish the design:

There is no need to construct a block (fetish, totem).
The block is integral with a PVC connector.

The multi-piece press-fit design lets you quickly make
new bodies with “experimental” finger hole locations.
You can test out new designs without constructing
a headjoint (mouthpiece, flue, sound hole, block).

The flute is tunable -
by slightly shifting how far the body slides into the headjoint,
the fundamental pitch of the flute can be adjusted.

The body is reversible, and produces a very different
and interesting scale.

If all goes right, you should have a Native American flute that tunes up to a Bb above Middle C.

Suggestion: Plan to make two or three of these flutes at the same time.
Construction of some of the parts takes a bit of skill that improves with
practice.

Caveats and Cautions:

This page does not advise you on the proper or safe used of tools.
Please seek training or advice on the use of any tools with which
you are not familiar.

Health issues regarding the use of PVC for musical instruments has
not been researched, to my knowledge.

PVC dust and shavings may be toxic.
If you sand, wear appropriate dust protection and consider
using a wet-sanding method while washing the dust particles
down the drain.

Note that this page is not a tutorial on how to build a
Native American flute!
This page gives specifications for the design,
and a general outline of the construction steps.
If you need specific help on construction, consult some of the excellent resources in the Native American flute groups listed on the
Roster of Discussion Groups
(especially the Native Flute Woodworking group).

A wedge-jig for holding the PVC tubing.
I made a simple “V”-shaped jig for holding the body straight
while drilling finger holes and for holding the
Throat piece while chiseling the flue and sound hole.

A precision caliper.

Click on any image on this page to see a larger version.

Overview

This diagram shows the main parts of this flute design:

Construction Steps:

1a. Cut 1/2″ (1.27cm) off the end of one of the two
PVC slip couplings.
This will be the Sleeve piece.

1b. Cut an 11.00″ (27.94cm)
length of PVC tubing for the Body.
This is longer than specified in the diagram.
This allows for tuning the flute by shaving off the bottom end.

1c. Cut a 2.15″ (2 5/32″, 5.46cm)
length for the Throat piece.

1d. On one end of the Throat,
mark in pencil the outline of the Flue and sound hole.
The marking should be 1.08″ (1 1/16″, 2.74cm) long and
0.25″ (1/4″, 0.63cm) wide.
The length of 1.08″ includes the flue length of 0.85″ (27/32″, 2.16cm)
and the length of the sound hole of 0.23″ (7/32″, 0.58cm).
Also mark the location of the back of the sound hole - 0.85″ from the end
of the Throat.

1e. Chisel straight cuts into the PVC
along the pencil lines for the flue area, but not for the sound hole area.

1f. Drill a hole with a 1/8″ bit in the center
of the sound hole box.
Use successively larger bits to enlargen the hole,
without encroaching on the pencil lines.

1g. File the back and front (fipple edge)
of the sound hole flat across the 1/4″ (0.63cm) wide width.
File the sides of the sound hole flat using a smaller file.

1h. Using the chisel from the end of the Throat,
chisel out the flue to a depth of about 0.02″ (1/64″, 0.5mm).
This takes some practice, so warm up on a scrap piece of PVC tubing.
The idea is to shave off even strips of PVC from one end of the flue
to the other.
Try to: keep an even curve to the bottom of the flue,
keep the depth of the flue even along it's length,
and have no gouges that would cause turbulence in the airstream.
If you don't have calipers, a dime is about 0.05″ (1.3mm) thick.

1i. Make a plug to fit into the inside of the Throat.
You'll need to get creative here.
You might find a cork of the correct size,
but most wine corks are a bit too small.
You might try a rubber stopper, if you can find one that fits.
A 3/4″ dowel will be too small, but a 1″ dowel can be sanded down
to the correct size (it is easier if you have a belt sander available).
If you sand down a dowel, it helps to mark a circle on the end
of the same size as the inside of the PVC tube.
The circle serves as a guide as to how much to sand and
helps to keep the dowel round.
Test your dowel for fit often.
Cut the plug to 0.85″ (27/32″, 2.16cm) long.

1j. Glue the Throat into the cut end of the Sleeve.
The throat should go 0.40″ (13/32″, 1.02cm) into the sleeve.
I used clear PVC glue without the primer.

1k. Insert the plug into the Throat so that the
front of the plug is flush with the beginning of the throat tube
and the back of the plug lines up with the back of the sound hole.
Glue the plug in place - contact cement works well here.
Let the glued up Throat and Sleeve cure.

Assembly

2a. Assemble the flute and try it out!
The Mouthpiece PVC slip joint goes over the end of the Throat
with the flue in it.
Because there are no finger holes, you only get one note.
Because the sound hole has no fipple edge and because the flue is shallow,
the note probably won't sound very good.

Sound Hole

3a. Dis-assmeble the 3 parts and “work” the sound hole and flue.
“Working” means to gradually:

file in a top and bottom bevel onto the fipple edge of the sound hole.

gradually make the flue deeper, keeping it smooth

Make small changes, and reassemble often to check the sound.
Ideally the fipple edge should line up in the "center" of the flue,
if the flue were extended all the way to the fipple edge.

3b. If you feel that you are not getting enough
air into the flue, consider removing a section of the small ring
in the center of the PCV slip joint mouthpiece part.
Also consider making a "ramp" at the beginning of the flue
(the side opposite the sound hole) for the first 1/10″ (0.25cm).

Finger Hole Layout

Once you are happy with the sound of the flute
without finger holes, then begin then:

4a. Draw a straight pencil line down the flute body
on which to line up the finger holes.

4b. Mark the locations of the centers of the
finger holes, as shown in the diagram below.
The measurements are also given in the table below.

Hole

Location

Diameter

Hole 1

2.37"2 12/32"6.02cm

0.30"19/64"0.76cm

Hole 2

3.17"3 11/64"8.05cm

0.32"20/64"0.81cm

Hole 3

4.90"4 29/32"12.45

0.30"19/64"0.76cm

Hole 4

5.93"5 30/32"15.06cm

0.28"18/64"0.71cm

Hole 5

6.85"6 27/32"17.40cm

0.27"17/64"0.68cm

4c. Assemble the flute and make sure the
finger hole locations are comfortable for your hands.
If not, you are free to move the hole locations around the body of the flute,
as long as the distance from the beginning of the body remains the same.
For example, moving the bottom hole towards the hand that is playing
(the ring finger of the right hand plays this hole for most people)
is a common modification.
You could also move the top hole to the back of the flute,
making it a thumb hole.
These modification are probably not needed on a flute of this size.

Tuning

5a. Drill the 5 finger holes using a 3/16″ drill bit.
Use extreme care in getting the holes centered correctly,
both lengthwise and aligned on the flute body.

5b. Play the basic scale and check the notes produced.
The target notes for this flute are:

Fingering

Note

All holes closed

A# (Bb)

Top 4 holes closed

C# (Db)

Top 3 holes closed

D# (Eb)

Top 2 holes closed

F

Top hole closed

G# (Ab)

All holes open

A# (Bb)

All notes, except possibly the bottom (all holes closed) note,
should play flat.

5c. (The Fun part)
Adjust the tuning of the flute a little
at a time based on the following general guidelines:

Select a temperature at which you expect to play.
A flute played at a different temperature
than it was tuned will produce different pitches.

Always work from the bottom of the flute (lowest notes) toward the
top of the flute (higher notes).
Do not adjust a note unless all the lower notes are in tune.

If the bottom note is flat, shorten the body of the flute.
You will probably wind up shortening the flute body by 1/4″ (0.63cm)
or so to bring it in line with the length specified in the diagram.

If a note is flat, make the topmost open hole for that note larger.

If a hole is getting too large for your fingers,
try undercutting the hole -
creating a slightly cone-shaped hole by removing material
around the hole on the inside of the flute bore,
but not on the surface of the flute.

Use your round file periodically to remove burrs or hairs dangling
from the finger holes - these affect how the flute plays!

Making a hole larger can be done by using the next larger sized drill bit,
or by filing out the hole with a round rasp.

You will find that every adjustment tends to affect every other adjustment
in addition to the one you are trying to change.
For example, making a hole larger will make that note sharper,
and all lower notes slightly flatter.
You will find that, once you get to the top of the scale,
you will need to start back at the bottom and re-adjust all the notes slightly.

Note that, if you change the shape of the sound hole or flue or fipple edge,
this can greatly affect the tuning.
It is best to completely finish fashioning the sound hole and flue before
you begin tuning.

5d. Try playing the flute with the body
inserted backwards.
I wound up with an interesting scale on mine!